Oral cough preparations, such as syrups, solutions, suspensions and the like, containing an effective antitussive agent have long been used for the symptomatic relief of coughs. The most popular of such preparations contain either dextromethorphan or its hydrobromide salt or codeine or its sulfate salt as the active antitussive agent.
Oral sore throat preparations, such as lozenges, sprays, solutions and the like, containing topical anesthetic/analgesic agents have long been used for the symptomatic relief of sore throat. Dyclonine HCl, a member of a class of compounds known as .beta.-aminopropiophenones and which is chemically denoted as 3-piperidino-4'-butoxypropiophenone hydrochloride, is a well known anesthetic/analgesic agent for topical use on the mucous membranes of the mouth and throat (see Federal Register, Vol. 47, No. 101, Proposed Rules, pages 22810-22813, 1982). Previous dosage forms of administration have included aqueous solutions of 0.1% dyclonine for use as a mouthwash, rinse or gargle, which is expelled from the oral cavity after use, and as a throat spray. Such forms provide topical application of an effective dose of dyclonine directly to the mucous membranes or mouth tissues. The ensuing anesthesia/analgesia lasts so long as an effective concentration of the dyclonine is supplied to the site of action. As the dyclonine is washed away, e.g., by saliva, the anesthetic/analgesia action recedes. Other dosage forms containing dyclonine HCl include solid lozenges containing 1.2 mg per lozenge for children and 3.0 mg per lozenge for adults (see Physicians' Desk Reference for Non-prescription Drugs, 8th Ed., 1987, pages 518-9). The benefit of dyclonine HCl is that it provides long-acting topical anesthetic relief. The mode of action is believed to be that it desensitizes sensory nerve receptors present in the mucous membranes of the throat and oral cavity to exert its local anesthetic effect.
The use of certain acids, particularly citric acid, to stabilize dyclonine HCl in anesthetic lozenges is reported in U.S. Pat. No. 4,139,627 to Lane et al., issued Feb. 13, 1979. The use of saccharin to stabilize dyclonine is disclosed in U.S. Ser. No. 311,155, filed Feb. 15, 1989 to Kelleher et al. In addition to its anesthetic/analgesic properties, dyclonine HCl is reported to possess antimicrobial activity. In this regard, U.S. Pat. No. 2,868,689 to Florestane et al., issued Jan. 13, 1959 discloses stabilized aqueous preparations of dyclonine HCl (0.1-5%) having topical anesthetic and antimicrobial action, the stabilization aspect being provided by the addition of chlorobutanol (0.1-0.5%).
Solid lozenge forms of the antitussive agent, dextromethorphan hydrobromide (10 mg), and phenol (32.5 mg) are known to be commercially available in Canada for the respective systemic treatment of coughs and local treatment of accompanying irritated throat. Also in British Patent No. 1,144,915, medicinal two-phase solid pastille forms containing (among others) dextromethorphan and phenol in the separate phases are disclosed for the respective treatment of cough and sore throat relief. Such solid lozenge and pastille forms require the action of saliva over an extended period of time for dissolution of the solid form, thereby effectuating release of the respective active ingredients and prolonged contact of phenol at the mucosal membrane throat site.
To date, however, applicants herein are unaware of any combination of an effective oral antitussive drug and dyclonine in a liquid composition for administration by immediate swallowing.
It has now been found that the combined use of dyclonine and an oral antitussive drug in a swallowable liquid provides improved relief to an individual afflicted with cough or cough and associated sore throat, without the aforementioned need for prolonged contact with mucosal membranes of the throat and oral cavity.